A vehicle system may include one or more powered vehicles that may be mechanically linked (directly or indirectly) to non-powered vehicles. The powered and non-powered vehicles of the vehicle system may travel as a group along a designated route. In cases where the vehicle system includes multiple powered vehicles, the vehicle system may coordinate operations of the powered vehicles to move the vehicle system. For example, a rail vehicle system may include a powered unit consist that has one or more powered units mechanically coupled to one or more non-powered rail cars. Vehicles in a consist may include a lead powered unit and one or more remote powered units and/or trail powered units. (Remote powered units are those that are spaced apart from the lead powered unit by one or more non-powered vehicles. Trail powered units are those that are in the same powered unit consist as the lead powered unit, and thereby not spaced apart from the lead powered unit by one or more non-powered rail vehicles, but that are subordinate to control by the lead powered unit.) The lead vehicle may control operation of one or more remote vehicles. More specifically, the lead vehicle (e.g., a lead locomotive) may coordinate tractive and braking operations of the different powered units (e.g., remote or trail locomotives) to control movement of the rail vehicle consist (e.g., a train). In some cases, a single train may include a plurality of such locomotive consists. The locomotive consists may communicate with one another to coordinate tractive and braking operations of the train.
In certain conventional vehicle systems, a lead vehicle communicates with remote powered vehicles via a multiple unit (MU) line. The information transmitted over the MU line is limited by the amount of wires or channels on the MU line. Thus, conventional MU communications do not identify a particular remote vehicle for which a command is intended. Instead, a similar command is sent to all remote vehicles. Similarly, conventional MU communications do not include information identifying a particular remote vehicle from which a status is sent. For example, a lead vehicle may receive an alarm, but not information indicating the particular remote vehicle from which the alarm was sent. Further, communications sent using conventional MU techniques may be quite limited in level of detail and/or fidelity.
These and other drawbacks of conventional communications among powered units of a consist may result in poor performance, limited flexibility of control, difficulty in troubleshooting and/or adjusting for changes in status of one or more vehicles, and the like.